posted on July 26, 2012 04:00
Tested: Trackmaster by Trackaroo
by Vince Illi
Data acquisition is a great way to become a better and faster driver. It lets you know what and where you need to improve and can help you determine exactly what the benefits and drawbacks of tuning are. That’s why professional race teams spend thousands of dollars on high-end data acquisition equipment. Amateurs have access to less-expensive data acquisition equipment, but a budget racer might have to choose between a set of track tires or a data logging box.
Until now, that is.
Trackmaster by Trackroo is an app for all Droid phones available from the Google Play store for only $4.99. Using the GPS and accelerometers built into your smart phone, Trackmaster turns that phone into a pretty complex data logger. It is designed with just about any type of corner-carving in mind, too. It can be set up both for circuit racing and one-way racing such as rally, autocross, and hill climbs. In my ongoing effort to improve my driving abilities, I downloaded Trackmaster and tried it out at my last autocross event.
Trackaroo has already put in track data for over 300 real-world race tracks. If you’re racing on one of them, you can just select your course and go. If, however, you’re dodging cones in a parking lot, the first step you need to do is input the course into your phone. The app makes this exceedingly easy, though. While walking the course, you input “split markers” using the built-in GPS on your phone. You only need two markers: the start and finish, but putting more in will give you more data to work with. I put in a total of 8 split markers: start and finish, plus 6 other ones at key portions of the course. Trackmaster shows you the location of these markers on Google Maps:
Obviously those parked cars weren’t there while I was driving.
Once you’ve loaded the course into your phone, you configure a few options, such as the type of course ("Lapping On" for circuit courses or "Lapping Off" for one-way events) and how to start and stop the timer. (I told it to start timing at the first split marker, since we were using a rolling start, and to stop timing at the last split marker.)
After that there was nothing left to do other than mount my phone in my car and start driving! Trackmaster sells some very nice suction mounts in their store, including one for motorcycles. I had an old Bracketron mount sitting in my garage, so I used that. Pushing the "Start" button before I launched started the timing automatically at the first split marker and stopped it at the last. My current elapsed time, split time, differentials (based on my previous best), and speed information were displayed on the phone where I could easily read them while driving:
This is the view you get while you’re actually driving. It's pretty easy to see if you turn the brightness all the way up, but you definitely need to plug the phone into a 12-volt source. Trackmaster will also read your times to you out loud at every split marker if you want it to!
Using only the phone’s built-in GPS, I found that my times as recorded by Trackmaster were within one or two tenths of the official time recorded by my club’s timing equipment. Trackaroo claims that the GPS is accurate to within 5 feet (~1.5 meters) when using built-in GPS. An external Bluetooth GPS can also be used for increased accuracy.
At the end of each run, Trackmaster immediately told me my total elapsed time and how much faster or slower I was than my previous best time. As cool as this is, it’s what you can do when you’re not driving that makes Trackmaster so amazing. Between the morning and afternoon runs, I was able to analyze how I was driving and where I could improve.
When viewing the data for a run, the first thing you see is a graphical outline of the lap superimposed on a GPS image of the track (or in this case parking lot).
Thursday, July 26, 2012 9:01 AM
Thanks for the write-up. I've been using the Torque app on my phone to datalog my autocross runs. The problem I have is that the GPS data is only 1 Hz, which I find insufficient for tight autox runs. However, the accelerometer I can get at 10Hz off my phone, which is nice. What logging rates does trackmaster allow?
I'm also logging TPS, Boost, RPM, and vehicle speed through the OBDII port (at 2Hz unfortunately). It doesn't do the track overlays but the OBD data is very nice to have.
Thursday, July 26, 2012 9:19 AM
Most phone GPSes are 1 Hz. External Bluetooh GPSes can have higher sampling rates.
Thursday, July 26, 2012 9:47 AM
Holy crap. Do they have an iPhone version? ... no. Dammit.
Thursday, July 26, 2012 10:26 AM
FYI I have been using this app for about 3 years now on and off track and not only does it work fantastic on the track (especially for the price) but its also a great way to find faster routes to and from work.
Thursday, July 26, 2012 11:48 AM
I'd have to agree with Mr. T, I've been using this for a while. Used first on my Evo4g and now on my new Samsung SIII with a 4.8" screen.
Thursday, July 26, 2012 1:10 PM
Did you find that consecutive runs line up well with each other and the actual course? I wrote my own app to log gps, and accel data and find that graphing latitude vs longitude no 2 runs line up. For lap or sector times it might be okay, but you can't analyze a line that way. Just standing still in a parking lot the gps jumps around quite a bit. In addition to the poor repeatability, for autocross the 1hz limit makes the gps data almost useless. Maybe it's just my phone (HTC Aria).
Thursday, July 26, 2012 1:13 PM
Also, issues with mapping the track aside, the quick transitions in autocross make 1hz really limit the usefulness of speed data from GPS.
That said, I'm sure it's great with external GPS.
Thursday, July 26, 2012 1:24 PM
No idea how it's *actually* working, but if you put a little thought in, you can figure out how it would be possible to use a 3-axis accelerometer as an inertial navigation system, and quite possible to do that and have the GPS to errorcheck it. I mean, it's collecting accelerometer data anyway...
Thursday, July 26, 2012 1:32 PM
I found it to be extremely accurate, even using the phone's internal GPS. The runs were very consistent with each other in terms of the GPS location data, and the timing data was within 1 or 2 tenths of the official time.
I'm not sure what sort of algorithm the program uses, but it is certainly using more than cellular-assisted GPS.
Thursday, July 26, 2012 1:43 PM
The accelerometer is to noisy to get accurate positional data. I tried it, it's bad news. Maybe they're smarter than me, but the problem is more fundamental than just an implementation issue. Other experts agree with me. I don't believe it can even be sanity checked by the gps and remain viable for position or speed.
They may have a good way to filter the gps to get rid of bad results. But again, I've only tried it on my phone with my own logger, results may vary.
Thursday, July 26, 2012 2:26 PM
Hey Vince. Interesting that you found the GPS data to be relatively accurate when compared to the autox timing system, because I did my own test of several data acq apps for the iPhone (for a tech story for Modified Mag a few years ago) including Harry's Lap Timer and none produced reliable lap times or reliable GPS data in general. As others have pointed out here, the reason for this is the phone's 1Hz GPS chipset, which only samples position once per second. Ask anyone in the racing data acquisition business and they'll tell you need at least a 10Hz chipset for reliable lap times (samples 10 times per second), accurate racing lines, and meaningful speed data. As a result, all the worthwhile yet affordable data acq systems use a 10Hz chipset (Driftbox, G2X, TraqMate, etc). The top-of-the-line Vbox units use 100Hz GPS, military grade accuracy, but that's overkill for most of us. That said, the accelerometer in the iPhone is quite accurate, so the lateral g data I collected using these iPhone apps did compare well to the standalone data acq systems I used in my comparison (Driftbox and G2X).
With the addition of an external GPS that uses a 10Hz (or better) chipset, smartphones with a good accelerometer and a user-friendly interface do become a really useful tool though.
Thursday, July 26, 2012 4:15 PM
Very cool app. I know where my next $5 is going! Oh and Vince, hope to see you at the BGP this year. I'll be in Turn 1, just like last year, though it'll only be on Sunday.
Thursday, July 26, 2012 4:54 PM
Oh snap. I got seats at turn 1, too, but I'm only going on Friday & Saturday. I'm way more of an ALMS fan than Indy. :-(
Sunday, July 29, 2012 7:55 AM
I created this video of yesterday's autoX using Trackmaster and Race Render:
Monday, July 30, 2012 10:18 AM
Hmm... this would be a fun app to input some favorite back road routes into. I wonder, can you share "track" maps with just friends and not the general public?
Monday, July 30, 2012 12:53 PM
I cannot confirm or deny that I use Trackmaster to set land-speed records on my daily commutes...
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